1. Field of the Invention
The present invention generally relates to a communication system, and more particularly, to a system for enabling a high-speed moving vehicle such as a train or an automobile to communicated with a base station.
2. Description of the Related Art
The communication between moving trains and automobiles is conventionally supported by leakage coaxial cable and sky wave. Japanese Patent Laid-Open Application No. 2002-33694, for example, discloses a wireless communication system that enables a moving vehicle to stably communicate with a base station, the system withstanding fading, shadowing, and phase noise. Japanese Patent Laid-Open Application No. 2001-204066, for example, discloses a system that enables a moving vehicle to communicate with a series of base stations arranged along a road.
The leakage coaxial cable is used for the communication between, for example, a super express train and the base station, and provides stable communication. The bandwidth of the leakage coaxial cable, however, is not wide enough to support high-speed communication. For this reason, it is rather difficult to provide passengers with better communication environment and to support smooth communication between staff on board and ground staff.
In addition, conventional wireless LAN technology requires high-speed handing over. That is, a moving vehicle at high speed needs to be handed over quickly from base station to base station. The high-speed handing over often fails due to various obstacles, which results in, for example, disconnection of the communication.